CN-121993139-A - Natural gas well sand-liquid separate drainage system and metering method

Abstract

The invention belongs to the technical field of oil and gas storage and transportation, and discloses a sand and liquid separate drainage system and a metering method of a natural gas well, wherein the system comprises a sand removal separator tank body, a first liquid level meter, a second liquid level meter, a sand drainage pipeline, a first electromagnetic flowmeter, a second electromagnetic flowmeter and a radar liquid level meter, wherein the first liquid level meter and the second liquid level meter are arranged on the sand removal separator tank body, one end of the sand drainage pipeline and one end of the liquid drainage pipeline are communicated with the sand removal separator tank body, the other end of the sand drainage pipeline and the other end of the liquid drainage pipeline are communicated with one end of the first electromagnetic flowmeter, the other end of the first electromagnetic flowmeter is communicated with the second electromagnetic flowmeter, the radar liquid level meter is arranged in a gas field pool, and an electric liquid drainage regulating valve is arranged on the liquid drainage pipeline. According to the invention, a sand-liquid separate drainage strategy is implemented through the sand drainage pipeline and the liquid drainage pipeline, and different liquid drainage modes are adopted in different periods, so that the service life of the electric valve can be effectively prolonged.

Inventors

• ZHANG XUEMING
• GONG YING
• SHEN YUHAN
• ZHANG ZUOWEI
• LU SHENGJIE
• LEI YU
• SHEN PENGYU
• HE HAOMIAO
• SONG XUECHUN
• Zhai Zhenjie
• Liang Diechen
• GUO YAOMING
• CHEN YICHENG
• WANG ZHEPENG

Assignees

• 中国石油天然气集团有限公司
• 北京石油机械有限公司
• 中国石油集团昆仑制造有限公司

Dates

Publication Date

20260508

Application Date

20251202

Claims (12)

1. 1. The sand-liquid separate drainage system of the natural gas well is characterized by comprising a sand-removal separator tank body (1), a first liquid level meter (2), a second liquid level meter (3), a sand drainage pipeline (4), a liquid drainage pipeline (9), a first electromagnetic flowmeter (14), a second electromagnetic flowmeter (17) and a radar liquid level meter (18); The first liquid level meter (2) is arranged on the sand removal separator tank body (1) and is positioned on one side of a sand collection bag of the sand removal separator tank body (1), and the second liquid level meter (3) is arranged on the sand removal separator tank body (1) and is positioned on one side of a liquid collection bag of the sand removal separator tank body (1); One end of the sand discharge pipeline (4) is communicated with a sand collecting bag of the sand removal separator tank body (1), one end of the liquid discharge pipeline (9) is communicated with a liquid collecting bag of the sand removal separator tank body (1), the other end of the sand discharge pipeline (4) and the other end of the liquid discharge pipeline (9) are communicated with one end of the first electromagnetic flowmeter (14), the other end of the first electromagnetic flowmeter (14) is communicated with the second electromagnetic flowmeter (17), the radar liquid level meter (18) is arranged in a gas field pool (19), and an electric liquid discharge regulating valve (11) is arranged on the liquid discharge pipeline (9).
2. 2. The natural gas well sand-liquid separate drainage system according to claim 1, wherein a first pneumatic cut-off valve (5) and a straight-through type oil nozzle (7) which are communicated in sequence are arranged on the sand drainage pipeline (4), and the pneumatic cut-off valve is positioned at one end of the sand drainage pipeline (4) close to the sand removal separator tank body (1).
3. 3. The sand-liquid separation system for the natural gas well according to claim 2, wherein a second pneumatic cut-off valve (10) is further arranged on the liquid discharge pipeline (9), one end of the second pneumatic cut-off valve (10) is communicated with a liquid collecting bag of the sand-removing separator tank body (1), and the other end of the second pneumatic cut-off valve is communicated with an electric liquid discharge regulating valve (11).
4. 4. A gas well sand and liquid displacement system according to claim 3, characterized in that a first valve (6) is arranged between the first pneumatic shut-off valve (5) and the through-type oil nozzle (7), and a second valve (8) is arranged at one end of the through-type oil nozzle (7) far away from the first valve (6).
5. 5. A gas well sand and liquid drainage system according to claim 3, characterized in that the end of the electric drainage regulating valve (11) remote from the second pneumatic shut-off valve (10) is provided with a third valve (12).
6. 6. A gas well sand and liquid separate drainage system according to claim 3, characterized in that a fourth valve (13) is arranged between the first electromagnetic flowmeter (14) and the sand drainage pipeline (4) and between the first electromagnetic flowmeter (14) and the second electromagnetic flowmeter (17), and a fifth valve (16) is arranged between the first electromagnetic flowmeter (14) and the second electromagnetic flowmeter (9).
7. 7. A gas well sand and liquid displacement system according to claim 1, characterized in that a partition is provided inside the desanding separator tank (1) between the sand collection bag and the liquid collection bag.
8. 8. A gas well sand and fluid displacement system according to any one of claims 3-6, further comprising a PLC control system (15), the PLC control system (15) comprising a monitoring component, a control component, a calculation component and an analysis component; The monitoring assembly is in signal connection with the first liquid level meter (2), the second liquid level meter (3), the first pneumatic cut-off valve (5), the second pneumatic cut-off valve (10), the electric liquid discharge regulating valve (11), the first electromagnetic flowmeter (14), the second electromagnetic flowmeter (17) and the radar liquid level meter (18), the monitoring assembly is respectively and electrically connected with the control assembly and the calculation assembly, and the analysis assembly is electrically connected with the calculation assembly.
9. 9. A method for metering a natural gas well production fluid, characterized in that the natural gas well sand-fluid separation system according to any one of claims 1-8 is used, comprising the following steps: Acquiring a count value of a second liquid level meter (3), judging whether the count value reaches the upper limit value of liquid discharge, if so, opening an electric liquid discharge regulating valve (11), closing the electric liquid discharge regulating valve (11) when the count value reaches the lower limit of liquid discharge, acquiring the instantaneous count value of opening and closing the electric liquid discharge regulating valve (11) through the second liquid level meter (3), and recording the action of the electric liquid discharge regulating valve (11) once; According to the count value of the second liquid level meter (3) and the action times of the electric liquid discharge regulating valve (11), the volume value corresponding to each millimeter of liquid level of the tank body (1) of the local desanding separator is called to calculate the liquid discharge amount, and the liquid discharge amount is checked through the count value of the first electromagnetic flowmeter (14); and calculating the liquid receiving amount of the gas field pool (19) according to the count value of the second electromagnetic flowmeter (17) and the count value of the radar liquid level gauge (18).
10. 10. A method of metering production fluid from a gas well according to claim 9 wherein the first pneumatic shut-off valve (5) is set to be normally open when the initial production fluid volume and sand volume of the gas well are greater than a set point.
11. 11. A method of metering natural gas well production fluids according to claim 9, wherein the first pneumatic shut-off valve (5) is opened and closed at regular intervals during the mid-or late-phase of gas well production.
12. 12. The method for measuring the produced fluid of the natural gas well according to claim 9, wherein the method for calculating the fluid discharge amount by calling the volume value corresponding to each millimeter of the fluid level of the tank body (1) of the local sand removal separator according to the count value of the second fluid level meter (3) and the action times of the electric fluid discharge regulating valve (11) comprises the following steps: Recording each action of the electric liquid discharge regulating valve (11), acquiring a count value of the second liquid level meter (3) when the electric liquid discharge regulating valve (11) is opened and closed, and calling a local storage volume value to calculate each liquid discharge amount, wherein each liquid discharge amount is a volume difference value corresponding to the count value of the second liquid level meter (3) when the electric liquid discharge regulating valve (11) is opened and closed instantaneously, and calculating the liquid discharge amount according to the opening times of the electric liquid discharge regulating valve (11) and each liquid discharge amount.

Description

Natural gas well sand-liquid separate drainage system and metering method Technical Field The invention belongs to the technical field of oil and gas storage and transportation, and particularly relates to a sand and liquid separate drainage system and a metering method of a natural gas well. Background For shale gas production process, reasonable gas well working system is an important means for realizing well fine management, improving single well EUR (ESTIMATED ULTIMATE RECOVERY, final recoverable reserves), and well liquid output plays a crucial role in well production system adjustment, and improving flowback liquid metering precision and accuracy is a key for adjusting gas well production system, so developing high-precision flowback liquid metering technology has become urgent need for realizing shale gas well fine management and fully releasing gas well productivity. At present, an electromagnetic flowmeter is adopted for measuring produced liquid, or a tank car is used for measuring after a gas field pool is directly discharged, and a two-phase flowmeter is arranged behind a wellhead throttling device for gas-liquid measurement at some stations. The electromagnetic flowmeter is independently used for measuring the liquid amount of the shale gas well from the beginning to the end of the full life cycle, and the fluctuation range is 400m 3/d-20m3/d due to the production characteristics of large liquid amount in the early stage and small liquid amount in the later stage of the shale gas well, and the electromagnetic flowmeter is a flow rate flowmeter, so that the liquid amount measured by the electromagnetic flowmeter at the back end of the gas-liquid separator has larger error due to the fact that the one-time selection cannot meet the requirement of the liquid amount measurement of the shale gas well from the beginning to the end of the full life cycle. For example, patent publication No. CN118728352a discloses a gas well production system and a gas well production metering method for a natural gas well having a metering function, which calculate the liquid discharge amount of a separator according to the number of operations and a liquid discharge threshold K, thereby calculating the liquid production amount of a gas well correspondingly connected to the separator. Although this patent has many advantages in improving the accuracy of formation produced fluid metering, it assumes pure fluid in the separator and does not take into account the effect of the degree of gas-liquid mixing on the single drainage volume V, resulting in a deviation from practice in the single drainage volume V value calculation. If the gas-liquid separation of the separator is incomplete, gas may be entrained during drainage, and the single drainage accuracy is further reduced. The patent emphasizes that the liquid level threshold K is converted to a V value by a volume conversion table, but all data in the examples use a fixed K value that would result in a metering deviation if the gas well liquid production rate fluctuates. If the pneumatic valve is "empty" (no liquid is discharged) or "missed" (liquid level overrun is not opened) due to the jamming of impurities or signal interference, the feedback mechanism still counts, resulting in the misalignment of the action times N. The patent with publication number CN105888643A discloses a system for automatically discharging and metering produced water of a shale gas well and a using method thereof, and the patent controls the opening and closing of each switch by a PLC (programmable logic controller) aiming at the high and low water level of a water storage tank through a liquid level transmitter, thereby realizing the automatic discharging and metering of the produced water. Although the scheme solves the problem of clamping stagnation of the traditional drain valve, the problem that a small-volume water storage tank is not suitable for a high-yield well exists, the electromagnetic valve is completely relied on in the mode, the electromagnetic valve acts for more than hundred times on daily average, abrasion of a sealing element is accelerated, and the leakage probability is increased. And the bypass valve needs to be manually operated, and sudden faults cannot be dealt with. In summary, when the conventional natural gas well uses the electromagnetic flowmeter to meter the flowback fluid after the separator, the accuracy of fluid metering is low, and the action frequency of the electric fluid discharge regulating valve is high, so that the problems of easy abrasion and the like exist. Disclosure of Invention Aiming at the problems, the invention provides a sand-liquid separate drainage system of a natural gas well, which comprises a sand-removing separator tank body, a first liquid level meter, a second liquid level meter, a sand drainage pipeline, a liquid drainage pipeline, a first electromagnetic flowmeter, a second electromagnetic flowmeter and a radar liquid level meter